1. Field of the Invention
The present invention relates to a tool and more particularly, to tool jaws positioned by relatively movable plural handles which have a spring-urged lock release.
2. Description of the Prior Art
Plier-type locking wrenches include tool jaws operable by a pair of handles. In operation, a locking lever locks a pivotal jaw in a position relative to a stationary jaw. A release lever releases the pivotal jaw from its locked position. Upon release of the pivotal jaw, a spring urges the pivotal jaw away from the stationary jaw. A threaded member cammingly engages the locking lever and is adjustable to adjust the locking position of the pivotal jaw.
Various plier-type locking wrenches have been devised. PCT Publication No. WO 82/03195, published Sep. 30, 1982, to Philippe Poux, discloses clamping pliers which meet the described plier-type locking wrench set forth above. Another tool similar to that described above is disclosed in U.K. Patent Application No. GB 2 234 701 A, published Feb. 13, 1991, to Ralph Peterson, who further discloses a rapid jaw adjustment mechanism for adjusting the position of the movable jaw relative to the fixed jaw. An expansion tool similar to the plier-type locking wrench set forth above is disclosed in U.S. Pat. No. 4,289,050, issued Sep. 15, 1981 to Vincent J. Scafaro. This expansion tool further includes an arrangement of spreading members engageable with the jaws of the plier-type locking wrench.
A self-adjusting locking wrench is disclosed in U.S. Pat. No. 3,600,986, issued Aug. 24, 1971 to Earl M. Baldwin, Jr. In contrast to the aforementioned threaded member, the self-adjusting locking wrench includes a self-adjusting locking unit interconnected between two handle units. The self-adjusting locking unit includes a toggle link. The toggle link cooperatively engages a spring biased, adjustable wedge and plate arrangement to automatically adjust the desired clamping pressure of the jaws.
A rope splicing implement structured and configured similar to that of the aforementioned plier-type locking wrench is disclosed in U.S. Pat. No. 3,654,755, issued Apr. 11, 1972 to Clarence R. Bell. Unlike the plier-type locking wrench, the handles of the rope splicing implement are operable to open the jaws; a threaded bolt is adjustable to vary the opening distance of the jaws; a tension spring maintains the jaws in an open position; and a release lever releases the jaws from the open position.
The foregoing implements are not satisfactory for use in narrowly confined areas where a plier-type locking wrench of extended length would be suitable. Tongs render possible the manipulation of one jaw relative to another jaw over an extended length. For example, U.S. Pat. No. 1,532,815, issued Apr. 7, 1925 to William J. Hahn, discloses tongs having jaws operable by a pair of handles. An adjustable connecting rod connects a movable jaw to a movable handle. The movable jaw is displacable relative to a fixed jaw by the movable handle.
An apparatus similar in construction to the aforementioned tongs is shown in U.S. Pat. No. 4,930,825, issued Jun. 5, 1990 to Timothy C. Dearman. Dearman discloses an apparatus for uprooting plants. A first jaw is movable relative to a second jaw. A clevis arrangement is coupled to an actuating mechanism by a connecting rod. The second jaw is movable, via the clevis arrangement, in response to movements of the actuating mechanism.
Though Hahn and Dearman are satisfactory for use in narrowly confined areas where a tool of extended length is necessitated, neither Hahn nor Dearman disclose locking jaws.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.